833C Data:

  DC Plate Voltage: 4000 Volts Max.

  DC Grid Voltage: -225 Volts

  DC Plate Current : 500 Milliamperes

  Filament -- Thoriated Tungsten

  Voltage ……………………10 volts

  Current ……………………10 amps

Animated gif of VTTC running w/30 inch sparks !

The 833C tube is a tri-electrode tube designed for use as a modulator, amplifier, and oscillator. This graphite-anode construction enables the 833C to dissipate a full 550 watts, exceeding industry standards by some 20 percent. At maximum ratings, the tube is cooled by forced air flow over the seals and envelop. The 833C utilizes a thoriated tungsten filament.

This dual 833C tube coil is an interesting creature indeed.  A voltage doubler using two 1000-watt microwave oven transformers and four microwave capacitors (1.25uf/2300v x4) are powering this coil.  The tank capacitors are Strontium Titanate doorknob capacitors (45kv, 2nf) which are built to withstand continuous, high frequency pulsed applications. A Staccato controller is driving the filaments to ground from 1 to 30bps. These 833C tubes are sturdy and can put up with a lot of stress. This coil took about six months to complete and was worth every minute as something about glowing red tubes that bring a sense of good old days when you had to warm up the tubes in the car A.M. radio…! Enjoy the links below. 


Grid Coil


Hot Sparks

Voltage Doubler